WO2020093312A1 - Lens assembly, fingerprint recognition apparatus and electronic device - Google Patents

Abstract

A lens assembly, a fingerprint recognition apparatus and an electronic device. The lens assembly comprises, in order from an object side to an image side, a first lens (31) and a second lens (32). The first lens comprises a first lens element having negative focal power. The first lens element is an S-shaped lens element having a convex object-side surface. At least one of two surfaces of the first lens element is aspheric. The second lens comprises a second lens element having positive focal power. The second lens element has two convex surfaces. At least one of the two surfaces of the second lens element is aspheric. Parameters of the lens assembly satisfy a first relationship, such that a field of view (FOV) of the lens assembly is greater than a first threshold.

Description

Lens group, fingerprint identification device and electronic equipment Technical field

The embodiments of the present application relate to the field of optical imaging, and more specifically, to a lens group, a fingerprint recognition device, and an electronic device.

Background technique

With the rapid development of the mobile phone industry, fingerprint recognition technology has been paid more and more attention, and the practicality of the off-screen fingerprint recognition technology has become a public demand. Under-screen fingerprint recognition technology is to collect the reflected light formed by the light emitted from the light source by the optical fingerprint sensor and reflected by the finger. The reflected light carries the fingerprint information of the finger, thereby realizing the under-screen fingerprint recognition. Among them, the fingerprint identification device can guide the optical signal returned by the finger through the lens system, and the reflected light needs to pass through the lens system to reach the optical fingerprint sensor. In order to obtain more fingerprint information, it is necessary to expand the field of view of the lens system as much as possible to collect fingerprint images of a larger area, but this will cause the designed lens system to be longer, to a certain extent, occupying the electronic device itself is small Vertical space. Therefore, how to obtain an appropriate field of view size without increasing the length of the lens system has become an urgent problem to be solved.

Summary of the invention

The embodiments of the present application provide a lens group, a fingerprint recognition device, and an electronic device, which can obtain an appropriate field of view size without increasing the length of the lens system, so as to realize the collection of fingerprint information in a large fingerprint collection area.

In a first aspect, a lens group is provided, including: a first lens and a second lens arranged in order from the object side to the image side. The first lens includes a first lens of negative power, the first lens is an S-shaped meniscus lens with a convex surface on the object side, and at least one of the two surfaces of the first lens is aspheric; The second lens includes a positive power second lens, the second lens is a biconvex lens, and at least one of the two surfaces of the second lens is aspheric;

Wherein, the parameters of the lens group satisfy the first relationship, so that the FOV of the lens group is greater than the first threshold, and the length of the lens group is less than the second threshold.

The parameters of the lens group include at least two of the following: the focal length f of the lens group, the focal length f ₁ of the first lens, the focal length f _{2 of} the second lens, and the focal length of the first lens A radius of curvature R1 toward the object side, a radius of curvature R2 toward the image side of the first lens, a radius of curvature R3 toward the object side of the second lens, and a radius toward the image side of the second lens Radius of curvature R4.

Therefore, the lens group of the embodiment of the present application arranges lenses with different powers, and each lens includes at least one aspherical surface, and the first relationship is satisfied by setting the lens group parameters, so that the lens group has a large FOV In order to realize the collection of fingerprint information in a larger fingerprint collection area, improve the fingerprint recognition performance of the optical fingerprint recognition device using the lens group.

In a possible implementation manner, the first relationship includes: 2.5 <f ₁ / R1 <4 and 0.5 <f ₁ /R2<2.0.

In a possible implementation manner, the first relationship further includes: 2.5 <f ₁ / R1 <4 and 0.5 <f ₁ /R2<2.0.

In a possible implementation manner, the first relationship further includes: -1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4.

In a possible implementation, the first relationship further includes: 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 < -1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3.

In a possible implementation, the first threshold is 100 degrees.

In a possible implementation, the second threshold is 2.6 mm.

In a possible implementation manner, the thickness CT1 of the first lens along the optical axis and the thickness CT2 of the second lens along the optical axis satisfy: 0.5 <CT1 / CT2 <1.5.

In a possible implementation manner, the distance TTL from the lower surface of the display screen to the imaging surface meets the focal length f of the lens group: 0.1 <f / TTL <0.2.

In a possible implementation manner, the maximum image height Y ′ on the imaging surface of the lens group, the distance TTL from the lower surface of the display screen to the imaging surface, and the focal length f of the lens group satisfy: 0.45 <Y '/(f*TTL)<0.6.

In a possible implementation manner, the refractive index of the material of the first lens n ₁ > 1.54, and the dispersion coefficient of the material of the first lens v ₁ > 55.50.

In a possible implementation manner, the refractive index of the material of the second lens n ₂ > 1.54, and the dispersion coefficient of the material of the second lens v ₂ > 55.98.

In a possible implementation manner, the lens group further includes: an aperture, disposed between the first lens and the second lens.

In a possible implementation manner, the TV distortion of the lens group is less than 5%, the relative illuminance of the lens group is greater than 30%, and the F number of the lens group is less than 1.6.

According to a second aspect, there is provided a fingerprint identification device, including a lens system, the lens system including a lens group as in the first aspect or any possible implementation manner of the first aspect, or including side-by-side arrangement along the radial Two of the lens groups.

In a possible implementation manner, the fingerprint identification device further includes an optical fingerprint sensor, which is disposed below the lens system and is used to receive the optical signal transmitted by the lens system and The optical signal is processed to obtain fingerprint information carried in the optical signal.

In a possible implementation manner, the fingerprint identification device further includes a bracket, wherein the lens system is interference-fitted into the bracket.

In a third aspect, an electronic device is provided, including the fingerprint identification device in the second aspect or any possible implementation manner of the second aspect.

In a possible implementation manner, the electronic device further includes a screen assembly including a display screen, foam and copper foil, and is disposed above the lens system in the fingerprint identification device. Wherein, the corresponding regions of the foam and the copper foil above the lens system are perforated to allow the optical signal including fingerprint information to enter the lens system.

BRIEF DESCRIPTION

FIG. 1 is a schematic plan view of an electronic device to which this application can be applied.

Fig. 2 is a schematic partial cross-sectional view of the electronic device shown in Fig. 1 along A-A '.

FIG. 3 is a schematic structural diagram of a lens group according to an embodiment of the present application.

4 is a schematic structural diagram of an optical fingerprint identification module according to an embodiment of the present application.

5 is a schematic diagram of a layout of a lens group according to an embodiment of the present application.

6 is a relative illuminance diagram of the lens group of the layout shown in FIG. 5.

7 (a) and 7 (b) are astigmatism and distortion diagrams of the lens group of the layout shown in FIG. 5, respectively.

FIG. 8 is an MTF diagram of the lens group of the layout shown in FIG. 5.

9 is a schematic diagram of another layout of a lens group according to an embodiment of the present application.

FIG. 10 is a relative illuminance diagram of the lens group of the layout shown in FIG. 9.

11 (a) and 11 (b) are astigmatism and distortion diagrams of the lens group of the layout shown in FIG. 9, respectively.

FIG. 12 is an MTF diagram of the lens group of the layout shown in FIG. 9.

13 is a schematic diagram of another layout of a lens group according to an embodiment of the present application.

14 is a relative illuminance diagram of the lens group of the layout shown in FIG. 13.

15 (a) and 15 (b) are astigmatism diagrams and distortion diagrams of the lens group of the layout shown in FIG. 13, respectively.

16 is an MTF diagram of the lens group of the layout shown in FIG. 13.

17 is a schematic structural diagram of a fingerprint identification device according to an embodiment of the present application.

18 is a schematic diagram of the positions of two lens groups included in the fingerprint identification device.

19 is a schematic block diagram of an electronic device according to an embodiment of the present application.

20 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings.

As the electronic device enters the era of full screen, the fingerprint collection area on the front of the electronic device is squeezed by the full screen, so the under-display (Under-display or Under-screen) fingerprint recognition technology has attracted more and more attention. Under-screen fingerprint recognition technology refers to installing a fingerprint recognition device, such as an optical fingerprint recognition device, below the display screen, so as to realize fingerprint recognition operations in the display area of the display screen, and there is no need to set a fingerprint on the front of the electronic device except the display area Collection area.

The fingerprint recognition technology under the optical screen uses the light returned from the top surface of the device display screen to perform fingerprint sensing and other sensing operations. The returned light carries information of an object (such as a finger) that is in contact with the top surface. By collecting and detecting the returned light, a specific optical fingerprint sensor located below the display screen is realized. The design of the optical fingerprint sensor may be to achieve the desired optical imaging by appropriately configuring the optical elements for collecting and detecting the returned light.

It should be understood that the technical solutions of the embodiments of the present application can be applied to various electronic devices, such as smart phones, notebook computers, tablet computers, game devices, and other portable or mobile computing devices, as well as electronic databases, automobiles, and bank automated teller machines (Automated Teller Machine) , ATM) and other electronic devices, but this embodiment of the present application is not limited thereto.

1 and 2 show a schematic diagram of an electronic device 100 to which the fingerprint identification device according to an embodiment of the present application can be applied, wherein FIG. 1 is a schematic front view of the electronic device 100, and FIG. 2 is along the electronic device 100 shown in FIG. AA 'partial cross-sectional structure diagram.

As shown in FIG. 1 and FIG. 2, the electronic device 100 includes a display screen 120 and an optical fingerprint recognition device (hereinafter also simply referred to as a fingerprint recognition device) 130, wherein the optical fingerprint recognition device 130 has one or more sensors An array, the sensing array is at least disposed in a partial area below the display screen 120, so that the fingerprint collection area (or sensing area) 103 of the optical fingerprint recognition device 130 is at least partially located in the display area 102 of the display screen 120 .

It should be understood that the area of the fingerprint collection area 103 may be different from the area of the sensing array of the optical fingerprint recognition device 130, for example, through optical path design such as lens imaging, reflective folding optical path design, or other optical path design such as light gathering or reflection , The area of the fingerprint collection area 103 of the optical fingerprint identification device 130 may be larger than the area of the sensing array of the optical fingerprint identification device 130. In other alternative implementations, if the light path is guided by, for example, light collimation, the fingerprint collection area 103 of the optical fingerprint identification device 130 may also be designed to be consistent with the area of the sensing array of the optical fingerprint identification device 130.

As shown in FIG. 1, the fingerprint collection area 103 is located in the display area 102 of the display screen 120. Therefore, when the user needs to unlock the electronic device or other fingerprint verification, he only needs to press his finger In the fingerprint collection area 103 located in the display screen 120, fingerprint input can be realized. Since fingerprint detection can be implemented within the screen, the electronic device 100 adopting the above structure does not require a special reserved space on the front to set fingerprint keys (such as the Home key), so that a full screen solution can be adopted, that is, the display area of the display screen 120 102 can be basically extended to the front of the entire electronic device 100.

As an embodiment, the display screen 120 may be a self-luminous display screen, which uses a self-luminous display unit as a display pixel, such as an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display screen or a micro light-emitting diode (Micro -LED) display screen. Taking an OLED display screen as an example, the optical fingerprint recognition device 130 may use the OLED display unit (ie, OLED light source) of the OLED display screen 120 located in the fingerprint recognition area 103 as an excitation light source for optical fingerprint detection.

In other embodiments, the optical fingerprint recognition device 130 may also use an internal light source or an external light source to provide an optical signal for fingerprint detection. In this case, the optical fingerprint recognition device 130 may be applicable to non-self-luminous display screens, such as liquid crystal display screens or other passive light-emitting display screens. Taking an LCD screen with a backlight module and a liquid crystal panel as an example, in order to support under-screen fingerprint detection of the LCD screen, the optical fingerprint system of the electronic device 100 may further include an excitation light source for optical fingerprint detection. The excitation light source may specifically be an infrared light source or a light source of a non-visible light of a specific wavelength, which may be provided under the backlight module of the liquid crystal display screen or the edge area under the protective cover of the electronic device 100, and the The optical fingerprint recognition device 130 may be disposed under the edge area of the liquid crystal panel or the protective cover and guided by the optical path so that the fingerprint detection light can reach the optical fingerprint recognition device 130; or, the optical fingerprint recognition device 130 may also be disposed at the Under the backlight module, and the backlight module allows the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optics through openings or other optical design of the film layers such as the diffusion sheet, the brightness enhancement sheet, the reflection sheet, etc. Fingerprint recognition device 130.

In addition, the sensing array of the optical fingerprint recognition device 130 is specifically a photodetector array, which includes a plurality of photodetectors distributed in an array, and the photodetectors can be used as the optical sensing unit as described above . When a finger touches, presses, or approaches (for ease of description, this application is collectively referred to as touch) on the fingerprint recognition area 103, the light emitted by the display unit of the fingerprint recognition area 103 reflects on the fingerprint on the surface of the finger and forms reflected light The reflected light of the ridges and valleys of the finger fingerprint is different. The reflected light is received from the display screen 120 and received by the photodetector array and converted into a corresponding electrical signal, that is, a fingerprint detection signal. Based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, thereby implementing an optical fingerprint recognition function in the electronic device 100.

It should be understood that, in a specific implementation, the electronic device 100 further includes a transparent protective cover 110, and the cover 110 may be specifically a transparent cover, such as a glass cover or a sapphire cover, which is located on the display screen 120 above and covering the front of the electronic device 100. Therefore, in the embodiment of the present application, the so-called finger touch, pressing or approaching on the display screen 120 actually refers to the finger touching, pressing or approaching the cover plate 110 above the display screen 120 or covering the cover plate 110 Surface of the protective layer. In addition, the electronic device 100 may further include a touch sensor, and the touch sensor may be specifically a touch panel, which may be provided on the surface of the display screen 120, or may be partially or wholly integrated into the display screen 120, namely The display screen 120 is specifically a touch display screen.

As an optional implementation manner, as shown in FIG. 2, the optical fingerprint recognition device 130 includes an optical detection unit 134 and an optical component 132, and the optical detection unit 134 includes the sensing array and the sensor array. The reading circuit and other auxiliary circuits that are sexually connected can be fabricated on a chip (Die) through a semiconductor process; that is, the optical detection unit 134 can be fabricated on an optical imaging chip or an image sensor chip (hereinafter also referred to as an optical fingerprint) Sensor or optical fingerprint sensor chip). The optical component 132 may be disposed above the sensing array of the optical detection unit 134, which may specifically include an optical filter (or filter, filter), an optical path guiding structure, and other optical elements. The filter can be used to filter out the ambient light penetrating the finger, and the light path guiding structure is mainly used to guide the light path such as collimating, modulating or converging the downward propagating light to realize the reflection from the finger surface The reflected light is guided to the sensing array for optical detection.

In a specific implementation, the optical component 132 may be packaged with the optical detection unit 134 in the same optical fingerprint chip, or the optical component 132 may be disposed outside the chip where the optical detection unit 134 is located, such as The optical component 132 is attached to the chip, or a part of the components of the optical component 132 is integrated into the chip. Among them, the optical path guiding structure of the optical component 132 has various implementation solutions, for example, it may be specifically an optical path modulator or an optical path collimator made of semiconductor silicon wafers or other substrates, which has multiple optical path modulation units or A collimating unit, the optical path modulation unit or the collimating unit may be specifically a micro-hole array. Alternatively, the light guide layer may also be an optical lens (Lens) layer, which has one or more lens units, such as a lens group composed of one or more aspheric lenses (hereinafter also referred to as a lens group). After the reflected light reflected from the finger is collimated or condensed by the micro-hole array or the lens unit, and received by the optical sensing unit below it, the sensing array can detect the fingerprint image of the finger .

A circuit board 140, such as a flexible printed circuit (FPC), may also be provided under the optical fingerprint recognition device 130, and the optical fingerprint recognition device 130 may be soldered to the circuit board 140 through pads, for example. In addition, the circuit board 140 realizes electrical interconnection and signal transmission with other peripheral circuits or other elements of the electronic device 100. For example, the optical fingerprint recognition device 130 may receive the control signal of the processing unit of the electronic device 100 through the circuit board 140, and may also output the fingerprint detection signal to the electronic device through the circuit board 140 100 processing unit or control unit.

In the embodiment of the present application, the lens group is used to collect the optical signal reflected from the finger above the display screen, and the optical signal is guided to the optical fingerprint sensor below the lens group. The optical signal carries the fingerprint information of the finger, thereby achieving optical Fingerprint recognition.

To facilitate better understanding, first briefly introduce the parameter indexes designed in the embodiments of the present application that can be used to evaluate the performance of the lens group.

Field of view (Field of View) (FOV): used to characterize the field of view of the lens. In the case of equal lens sizes, the larger the FOV of the lens, indicating that the lens can obtain information in a larger area, that is, using the lens can obtain The amount of information is greater.

Aperture value or F-number (F-number, Fno): the reciprocal of the lens relative aperture, used to characterize the amount of light entering the sensor array of the optical fingerprint device through the lens. The smaller the F number, the more light enters the lens.

TV distortion: used to measure the degree of visual distortion of an image. It can be understood that the smaller the TV distortion, the better the imaging effect.

Relative Illumination (RI): refers to the ratio of the illuminance of different coordinate points on the imaging surface to the illuminance of the center point. The smaller the relative illuminance, the more uneven the illuminance on the imaging surface, which is likely to cause underexposure or overcenter in certain positions The problem of exposure affects the imaging quality; the greater the relative illuminance, the higher the imaging quality.

FIG. 3 is a schematic structural diagram of a lens group according to an embodiment of the present application. As shown in FIG. 3, the lens group 30 includes a first lens 31 and a second lens 32 that are arranged in order from the object side to the image side.

Wherein, the first lens 31 includes a negative power first lens, the first lens is an S-shaped meniscus lens with a convex surface on the object side, and at least one of the two surfaces of the first lens is aspheric; The second lens 32 includes a second lens of positive power, the second lens is a biconvex lens, and at least one of the two surfaces of the second lens is aspheric.

It should be understood that in the embodiment of the present application, the first lens may be a lens, that is, a first lens, or may be a group of lenses, as long as the combined power of the group of lenses is negative power; the same The second lens may also be a single lens, that is, a second lens, or a group of lenses, as long as the combined power of the group of lenses is positive power. The following uses the first lens as the first lens and the second lens as the second lens as examples. For example, the first lens and the second lens may be made of resin material or other plastic materials, which is not limited here.

Further, the parameters of the lens group satisfy the first relationship, so that the FOV of the lens group is greater than the first threshold, and the length of the lens group is less than the second threshold. The parameters of the lens group include at least two of the following: the focal length f of the lens group, the focal length f ₁ of the first lens, the focal length f ₂ of the second lens, and the side of the first lens facing the object side Radius of curvature R1, radius of curvature R2 of the first lens facing the image side, radius of curvature R3 of the second lens facing the object side, and radius of curvature R4 of the second lens facing the image side.

In this embodiment, the lens group is arranged with lenses of different powers, and each lens includes at least one aspherical surface, and the first relationship is satisfied by setting the lens group parameters, so that when the length of the lens group is constant It has a large FOV to realize the collection of fingerprint information in a large fingerprint collection area and improve the fingerprint recognition performance of the optical fingerprint recognition device using the lens group. In other words, in the case of obtaining FOVs of the same size, the length of the lens group is reduced, thereby reducing the longitudinal space occupied when the lens group is mounted on an electronic device.

The first relationship satisfied by the parameters of the lens group may include at least one of the following parameter relationships: the relationship between f ₁ and R1 and R2, for example, f ₁ / R2 is within a preset value range, f ₁ / R2 is in the preset value range; the relationship between f ₂ and R3 and R4, for example, f ₂ / R3 is in the preset value range, f ₂ / R4 is in the preset value range; f, The relationship between f ₁ and f ₂ , for example, f / f _{1 is} within the preset value range, f / f _{2 is} within the preset value range, f ₁ / f _{2 is} within the preset value range; R1 , R2, R3 and R4, for example, R1 / R2 is in the preset value range, R1 / R3 is in the preset value range, R1 / R4 is in the preset value range, R2 / R3 is in Within the preset value range, R2 / R4 is within the preset value range, R3 / R4 is within the preset value range, etc.

The FOV of the lens group is greater than the first threshold and the length of the lens group is less than the second threshold. The first threshold may be, for example, 100 degrees, and the second threshold may be, for example, 2.6 mm. By simulating the lens group, and Combining the empirical value, the first relationship that should be satisfied between the above parameters can be obtained.

For example, the first relationship includes: 2.5 <f ₁ / R1 <4 and / or 0.5 <f ₁ /R2<2.0.

For another example, the first relationship includes: 0.2 <f ₂ /R3<0.5 and / or -2 <f ₂ / R4 <-1.

For another example, the first relationship includes at least one of the following: -1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4.

For another example, the first relationship includes at least one of the following: 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1 , 5 <R2 / R4 <12, -8 <R3 / R4 <-3.

It should be understood that the lens group may satisfy all the above-mentioned parameter relationships, or may also satisfy some of the parameter relationships, and only needs to ensure that the FOV is greater than the first threshold. For example, when 2.5 <f ₁ / R1 <4 and 0.5 <f ₁ /R2<2.0 are satisfied, the lens group can meet the requirement of FOV greater than 100 degrees, and effectively reduce the length of the lens group (from the lower surface of the screen to the image surface Distance), for example, the length of the lens group is less than 2.6mm, so as to reduce the longitudinal space occupied by the lens group when it is assembled in an electronic device; further, when 0.2 <f ₂ /R3<0.5 and / or -2 <f ₂ / R4 <-1, the aberration of the lens group can be effectively controlled to effectively improve the imaging quality of the lens group; further, when -1 <f / f ₁ <0, 0 <f / f ₂ <1 , -8 <f ₁ / f ₂ <-4, you can reduce the depth of field of the lens group, thereby improving the imaging quality on a specific surface, such as the imaging quality on the surface of the screen; further, when 0.2 <R1 is satisfied /R2<0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3 At this time, the sensitivity of the lens group, that is, the degree to which manufacturing errors affect the imaging effect can be reduced, thereby improving the yield of the lens group during the manufacturing process.

Based on this, it can be seen that by setting various parameters in the lens group, the lens group can have the performance of large FOV, small working F number, small TV distortion and large relative illuminance, which is conducive to improving the fingerprint recognition mode using the lens group Group fingerprint recognition performance.

Optionally, in some embodiments, the thickness CT1 of the first lens in the optical axis direction and the thickness CT2 of the second lens in the optical axis direction also satisfy a preset relationship, for example, satisfy 0.5 <CT1 / CT2 < 1.5, by which the structure of the lens group becomes stronger, thereby increasing the service life of the lens group.

Optionally, in some embodiments, the distance between the lower surface of the display screen and the imaging plane (Total Trace Length, TTL) and the focal length f of the lens group satisfy a preset relationship, for example, satisfy 0.1 <f / TTL <0.2 . When meeting the imaging requirements of the lens group, the miniaturization of the lens group is maintained, and the freedom of assembling the lens group in electronic equipment is improved.

Optionally, in some embodiments, the maximum image height Y ′ on the imaging surface of the lens group, the distance TTL from the lower surface of the display screen to the imaging surface, and the focal length f of the lens group also satisfy a preset relationship, For example, satisfy 0.45 <Y '/ (f * TTL) <0.6. Since the size of TTL determines the size of the focal length f of the lens group, or the size of the size of the lens group, it is possible to make the lens group have With a shorter focal length and a larger FOV, it maximizes the effective photosensitive area of the optical fingerprint sensor, that is, the area of the sensing array, thereby improving imaging resolution.

Optionally, in some embodiments, the refractive index and dispersion coefficient of the material of the first lens also satisfy a preset relationship, for example, the directivity n ₁ > 1.54 of the material of the first lens, the material of the material of the first lens The dispersion coefficient v ₁ > 55.50. To meet the requirements of dispersion and reduce production costs, this configuration can provide a suitable balance of phase difference.

Optionally, in some embodiments, the refractive index and dispersion coefficient of the material of the second lens also satisfy a preset relationship, for example, the refractive index n ₂ > 1.54 of the material of the second lens, the material of the second lens The dispersion coefficient v ₂ > 55.98. To meet the requirements of dispersion and reduce production costs, this configuration can provide a suitable balance of phase difference.

In the embodiment of the present application, when the parameters of the lens group satisfy the first relationship, in addition to making the FOV greater than the first threshold, the parameters such as the F number, TV distortion, and relative illuminance of the lens group can also be in appropriate ranges. For example, the F number of the lens group is less than 1.5, which can allow enough light to enter the lens group, which is conducive to collecting weak fingerprint signals, and can also shorten the exposure time and reduce power consumption. For another example, the TV distortion of the lens group is less than 5%, which is beneficial to avoid the influence of moiré fringes on fingerprint imaging. For another example, the relative illuminance of the lens group is greater than 30%, which is conducive to improving imaging quality.

Optionally, in some embodiments, the lens group further includes an aperture (or may also be referred to as an aperture), and the aperture is disposed between the first lens and the second lens.

The diaphragm can be used to adjust the size of the optical signal or imaging range. By setting the diaphragm to adjust the optical signal or imaging range, the optical signal carrying fingerprint information can be imaged to the optical fingerprint sensor to the greatest extent, so that the optical fingerprint sensor Can get more fingerprint information, further improve the resolution of fingerprint recognition.

Optionally, in some embodiments, physical parameters such as the radius of curvature, thickness, material, effective diameter, and conic coefficient of each structural member (eg, first lens, second lens, diaphragm) in the lens group can be controlled , And / or, the aspherical higher-order coefficients of the aspherical lenses in the lens group (such as the even-order terms in A2 to A16, etc.), so that the parameters of the lens group satisfy the first relationship described above, thereby making the lens The FOV of the group is greater than 100 degrees, the TV distortion of the lens group is less than 5%, the relative illuminance of the lens group is greater than 30%, and the F number of the lens group is less than 1.5, which will be described in detail below in conjunction with specific embodiments.

It should be understood that the lens group of the embodiment of the present application can be applied to an optical fingerprint identification device, and the lens group can cooperate with the optical fingerprint sensor in the optical fingerprint identification device to realize the fingerprint of a larger fingerprint collection area in a limited space Information imaging; alternatively, the lens group can also be used in other devices or devices that require high optical imaging performance, which is not limited here.

4 is a schematic structural diagram of an optical fingerprint recognition device using the lens group of the embodiment of the present application. As shown in FIG. 4, the optical fingerprint recognition device 400 may include: infrared filter (Infrared Filter, IR) 401, IR filter bonding glue 402, chip (DIE) 403, DIE bonding glue 404, flexible A circuit board (Flexible Printed Circuit, FPC) 405, a reinforcement board 406, a bracket 407, and a lens group 409.

Among them, the IR Filter is used to filter infrared light to avoid infrared light affecting the fingerprint imaging;

The IR filter bonding glue 402 is used to bond the IR filter 401 and DIE403;

DIE 403, which can be an optical imaging chip, etc., which can specifically correspond to the light detection section 134 in FIG. 1, is used to convert an optical signal into an electrical signal to obtain a fingerprint image of a finger above the optical fingerprint recognition device; DIE 403 can Used in conjunction with lens group 409 to convert the optical signals imaged by the lens group 409 into electrical signals;

DIE bonding glue 404 is used to fix DIE 403 and FPC 405.

FPC405, used to connect the circuit in the electronic equipment installed in the DIE403 and the optical fingerprint recognition device;

A bracket 407 is used to fix the lens group 409 and DIE 403 to control the accuracy of defocus and eccentricity.

A screen assembly is further provided above the optical fingerprint recognition device 400, and the screen assembly includes a display screen 410, a foam 411, and a copper foil 412.

In the embodiment of the present application, the lens group 409 can be fitted in the bracket 407 with interference, so that the lens group 409 and the DIE 403 fit together, and each structural part of the optical fingerprint identification device can be adhered to Together, further, the optical fingerprint identification device may be fixed in the middle frame 408 of the electronic device.

Since the optical signal transmission is required between the lens group 409 and the display screen 410, the foam 411 and the aluminum foil 412 in the screen assembly corresponding to the lens group 409 need to be opened to make the lens group 409 within the FOV range The optical signal can pass.

Hereinafter, the performance of the lens group according to the embodiment of the present application will be specifically described in combination with Embodiment 1, Embodiment 2 and Embodiment 3.

Example 1

The lens group includes two lenses (a first lens and a second lens) and an aperture. FIG. 5 shows the layout of the lens group, in which the display side, the first lens, and the Aperture, second lens, IR filter, filter glue. The first lens is a concave lens, and the second lens is a convex lens.

In order to distinguish and describe, in order from the object side to the image side, the upper and lower surfaces of the display are denoted as S1 and S2, the two surfaces of the first lens are denoted as S3 and S4, and the surface of the diaphragm is denoted as S5 The two surfaces of the second lens are denoted as S6 and S7, the surface of the IR filter is denoted as S8 and S9, the surface of the filter adhesive is denoted as S10 and S11, and the imaging surface is S12.

Further, by setting at least one of the radius of curvature, thickness, material, effective diameter, and conic coefficient of each face in the lens group, and / or the aspheric high-order term of the aspheric lens in the lens group Coefficients A2, A4, A6, A8, A10, A12, A14, A16, so that the parameters of the lens group satisfy the above first relationship, so that the FOV of the lens group is greater than 100 degrees, the TV distortion is less than 5%, and the F number is less than 1.5, and the relative illuminance is greater than 30%.

In Example 1, the parameters of the first lens group satisfies a predetermined relationship and the other relationship _{comprises: 2.5 <f 1 /R1<4,0.5<f 1 /R2<2.0,2.5<f} 1 / R1 <4, 0.5 <f ₁ /R2<2.0, _-1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4, 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3, 0.1 <f / TTL < 0.2, 0.45 <Y '/ (f * TTL) <0.6, n ₁ > 1.54, v ₁ > 55.50, n ₂ > 1.54, v ₂ > 55.98.

For example, in Example 1, the radius of curvature, thickness, material, effective diameter, and conic coefficient of each surface in S1 to S12 can be set using the corresponding parameters in Table 1. The coefficients of higher order terms adopt the parameters shown in Table 2.

Table 1

surface Surface type Radius of curvature thickness material Effective diameter Conic coefficient S1 Object endless 1.500 BK7 2.800 A S2 Sphere endless 0.730 A 1.888 A S3 Aspherical -0.917 0.369 APL5014CL 0.780 -0.793 S4 Aspherical -3.314 0.209 A 0.334 -449.4978 S5 Aperture endless 0.029 A 0.198 A S6 Aspherical 1.105 0.383 APL5014CL 0.230 -12.050 S7 Aspherical -0.318 0.428 A 0.300 -0.152 S8 Sphere endless 0.21 D263TECO 0.714 A S9 Sphere endless 0.020 BK7 0.714 A S12 Face A A A 0.619 A

It should be noted that in the first embodiment, S9 and S10 can be regarded as the same surface, S11 and S12 can be regarded as the same surface, that is, S10 and S9 correspond to the same parameter, and the parameters of S12 and S11 correspond to the same parameter, The parameters corresponding to S10 and S11 are not shown.

Table 2

surface A2 A4 A6 A8 A10 A12 A14 A16 S3 A 2.376 -2.650 -15.248 103.052 -268.292 335.261 -162.505 S4 A -6.043 827.466 -3.145e4 6.779e5 -8.129e5 5.054e7 -1.253e8 S6 A 1.219 -135.446 -1042.138 5.727e4 -4.766e4 -6.025e4 -9.217e7 S7 A 6.410 81.283 -996.731 9.470e4 -1.712e6 1.317e7 -3.648e7

Based on the parameters shown in Table 1 and Table 2, the parameters of the lens group shown in Example 1 can be determined as follows: TTL = 2.37666mm (that is, the distance from S2 to S12), f ₁ = -2.4486, f ₂ = 0.49849, f = 0.444242 mm, R1 = -0.917, R2 = -3.314, R3 = 1.105, R4 = -0.318, Y '= 0.61. Wherein, f ₁ /R1=2.670229,f ₁ /R2=0.738865,f ₂ /R3=0.451122 and _{f 2 /R4=-1.56758,f/f 1 = -0.181427, f} / f 2 = 0.891175, f 1 / f ₂ = -4.91203, R1 / R2 = 0.276705, R1 / R3 = -0.82986, R1 / R4 = 2.883648, R2 / R3 = -2.9991, R2 / R4 = 10.42138, R3 / R4 = -3.447484, f / TTL = 0.186919, n ₁ = n ₂ = 1.5445, Y '/ (f * TTL) = 0.577754, CT1 / CT2 = 0.963446, v ₁ = v ₂ = 55.9867. It can be seen that the parameters of the lens group all satisfy the foregoing first relationship and the foregoing other preset relationships. Under the above parameters, FIG. 6 to FIG. 8 are the relative illuminance map, astigmatism map, TV distortion map, and modulation transfer function (MFT) map of the lens group in this order.

From the simulation diagrams shown in FIGS. 6 to 8, it can be concluded that the FOV of the lens group is 105 degrees, the working F number is 1.47156, the TV distortion is 0.3268%, and the relative illumination is 30%. Therefore, in the case where the parameters of the lens group satisfy the aforementioned first relationship, the lens group has the performance of large FOV, small working F-number, small TV distortion, and high relative illuminance.

Example 2

The lens group includes two lenses (a first lens and a second lens) and an aperture. FIG. 9 shows the layout of the lens group, in which the display screen, the first lens, and the Aperture, second lens, IR filter, filter glue. The first lens is a concave lens, and the second lens is a convex lens.

In order to distinguish and describe, in order from the object side to the image side, the upper and lower surfaces of the display are denoted as S1 and S2, the two surfaces of the first lens are denoted as S3 and S4, and the surface of the diaphragm is denoted as S5 The two surfaces of the second lens are denoted as S6 and S7, the surface of the IR filter is denoted as S8 and S9, the surface of the filter adhesive is denoted as S10 and S11, and the imaging surface is S12.

Further, by setting at least one of the radius of curvature, thickness, material, effective diameter, and conic coefficient of each face in the lens group, and / or the aspheric high-order term of the aspheric lens in the lens group Coefficients A2, A4, A6, A8, A10, A12, A14, A16, so that the parameters of the lens group satisfy the above first relationship, so that the FOV of the lens group is greater than 100 degrees, the TV distortion is less than 5%, and the F number is less than 1.5, and the relative illuminance is greater than 30%.

In Example 2, the parameters of the first lens group satisfies a predetermined relationship and the other relationship _{comprises: 2.5 <f 1 /R1<4,0.5<f 1 /R2<2.0,2.5<f} 1 / R1 <4, 0.5 <f ₁ /R2<2.0, _-1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4, 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3, 0.1 <f / TTL < 0.2, 0.45 <Y '/ (f * TTL) <0.6, n ₁ > 1.54, v ₁ > 55.50, n ₂ > 1.54, v ₂ > 55.98.

For example, in Example 2, the curvature radius, thickness, material, effective diameter, and conic coefficient of each surface in S1 to S12 can be set using the corresponding parameters in Table 3, and the aspheric surface in S1 to S12 The coefficients of higher order terms adopt the parameters shown in Table 4.

table 3

surface Surface type Radius of curvature thickness material Effective diameter Conic coefficient S1 Object endless 1.5 BK7 2.800 A S2 Sphere endless 1.030 A 2.054 A S3 Aspherical -0.765 0.352 APL5015AL 0.741 -2.086 S4 Aspherical -1.646 0.198 A 0.328 -473.887 S5 Aperture endless 0.014 A 0.189 A S6 Aspherical 1.081 0.345 APL5014CL 0.234 2.872 S7 Aspherical -0.288 0.372 A 0.303 -0.287 S8 Sphere endless 0.21 D263TECO 0.450 A S9 Sphere endless 0.02 BK7 0.553 A S12 Face A A A 0.537 A

It should be noted that in the second embodiment, S9 and S10 can be regarded as the same surface, and S11 and S12 can be regarded as the same surface, that is, S10 and S9 correspond to the same parameter, and the parameters of S12 and S11 correspond to the same parameter, The parameters corresponding to S10 and S11 are not shown.

Table 4

surface A2 A4 A6 A8 A10 A12 A14 A16 S3 A 2.993 -4.078 -28.910 222.140 -677.996 -1008.13 -586.197 S4 A -11.368 1363.600 -5.817e4 1.460e6 -2.077e7 1.540e8 -4.570e8 S6 A -3.335 -2.755 -1654.813 1.039e5 -1.132e6 -6.601e6 1.429e8 S7 A 9.852 -178.693 -1557.330 2.091e5 -4.405e6 3.892e7 -1.223e8

Based on the parameters shown in Tables 3 and 4, the parameters of the lens group shown in Example 2 can be determined as follows: TTL = 2.3775 mm (ie, the distance from S2 to S12), f ₁ = -3.3167, f ₂ = 0.47697, f = 0.447816 mm, R1 = -0.765, R2 = -1.646, R3 = 1.081, R4 = -0.288, Y '= 0.58. Wherein, f ₁ /R1=3.042844,f ₁ /R2=1.104462,f ₂ /R3=0.224562 and _{f 2 /R4=-1.70346,f/f 1 = -0.135019, f} / f 2 = 0.938877, f 1 / f ₂ = -6.953687, R1 / R2 = 0.36297, R1 / R3 = -0.51318, R1 / R4 = 3.89286, R2 / R3 = -1.41384, R2 / R4 = 10.725, R3 / R4 = -7.58571, f / TTL = 0.188356, n ₁ = n ₂ = 1.5445, Y '/ (f * TTL) = 0.544763, CT1 / CT2 = 0.89425, v ₁ = v ₂ = 55.9867. It can be seen that the parameters of the lens group all satisfy the foregoing first relationship and the foregoing other preset relationships. Under the above parameters, Figures 10 to 12 are the relative illuminance map, astigmatism map, TV distortion map, and MFT map of the lens group in this order.

From the simulation diagrams shown in FIGS. 10 to 12, it can be concluded that the FOV of the lens group is 110 degrees, the working F number is 1.46254, the TV distortion is 0.0603%, and the relative illumination is 30%. Therefore, in the case where the parameters of the lens group satisfy the aforementioned first relationship, the lens group has the performance of large FOV, small working F-number, small TV distortion, and high relative illuminance.

Example 3

The lens group includes two lenses (a first lens and a second lens) and an aperture. FIG. 13 shows the layout of the lens group, in which the display side, the first lens, and the Aperture, second lens, IR filter, filter glue. The first lens is a concave lens, and the second lens is a convex lens.

In order to distinguish and describe, in order from the object side to the image side, the upper and lower surfaces of the display are denoted as S1 and S2, the two surfaces of the first lens are denoted as S3 and S4, and the surface of the diaphragm is denoted as S5 The two surfaces of the second lens are denoted as S6 and S7, the surface of the IR filter is denoted as S8 and S9, the surface of the filter adhesive is denoted as S10 and S11, and the imaging surface is S12.

Further, by setting at least one of the radius of curvature, thickness, material, effective diameter, and conic coefficient of each face in the lens group, and / or the aspheric high-order term of the aspheric lens in the lens group Coefficients A2, A4, A6, A8, A10, A12, A14, A16, so that the parameters of the lens group satisfy the above first relationship, so that the FOV of the lens group is greater than 100 degrees, the TV distortion is less than 5%, and the F number is less than 1.5, and the relative illuminance is greater than 30%.

In Example 3, the parameter of the first lens group satisfies a predetermined relationship and the other relationship _{comprises: 2.5 <f 1 /R1<4,0.5<f 1 /R2<2.0,2.5<f} 1 / R1 <4, 0.5 <f ₁ /R2<2.0, _-1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4, 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <-0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3, 0.1 <f / TTL < 0.2, 0.45 <Y '/ (f * TTL) <0.6, n ₁ > 1.54, v ₁ > 55.50, n ₂ > 1.54, v ₂ > 55.98.

For example, in Embodiment 3, the radius of curvature, thickness, material, effective diameter, and conic coefficient of each surface in S1 to S12 can be set using the corresponding parameters in Table 5, and the aspheric surface in S1 to S12 The coefficients of higher order terms adopt the parameters shown in Table 6.

table 5

surface Surface type Radius of curvature thickness material Effective diameter Conic coefficient S1 Object endless 1.5 BK7 2.8 A S2 Sphere endless 0.940 A 1.903 A S3 Aspherical -1.090 0.313 APL5014CL 0.611 -1.365 S4 Aspherical -3.003 0.136 A 0.611 107.555 S5 Aperture endless 0.010 A 0.182 A S6 Aspherical 2.124 0.348 APL5014CL 0.205 65.410 S7 Aspherical -0.280 0.400 A 0.287 -0.406 S8 Sphere endless 0.21 D263TECO 0.533 A S9 Sphere endless 0.02 BK7 0.591 A S12 Face A A A 0.597 A

It should be noted that in this embodiment 3, S9 and S10 can be regarded as the same surface, S11 and S12 can be regarded as the same surface, that is, S10 and S9 correspond to the same parameters, and the parameters of S12 and S11 correspond to the same parameters, The parameters corresponding to S10 and S11 are not shown.

Table 6

surface A2 A4 A6 A8 A10 A12 A14 A16 S3 A 2.976 -3.625 -28.550 223.179 -676.039 1030.329 -651.376 S4 A -5.917 1323.094 -5.719e4 1.414e6 -1.970e7 1.444e8 -4.283e8 S6 A 4.050 -182.362 -5319.101 1.587e5 3.753e5 1.918e7 -6.707e8 S7 A 6.008 -117.483 -1813.586 2.030e5 -4.438e6 3.874e7 -1.129e8

Based on the parameters shown in Tables 5 and 6, the parameters of the lens group shown in Example 3 can be determined as follows: TTL = 2.54 mm (that is, the distance from S2 to S12), f ₁ = -3.0433 mm, and f ₂ = 0.4557 mm , F = 0.397686 mm, R1 = -1.090, R2 = -3.003, R3 = 2.124, R4 = -0.280, Y '= 0.501. Wherein, f ₁ /R1=3.97817,f ₁ /R2=1.848906,f ₂ /R3=0.421554 and _{f 2 /R4=-1.58229,f/f 1 = -0.130676, f} / f 2 = 0.872693, f 1 / f ₂ = -6.678297, R1 / R2 = 0.46474, R1 / R3 = -0.707768, R1 / R4 = 2.65625, R2 / R3 = -1.52266, R2 / R4 = 5.715278, R3 / R4 = -3.775347, f / TTL = 0.156569, n ₁ = n ₂ = 1.5445, Y '/ (f * TTL) = 0.495979, CT1 / CT2 = 1.02029, v ₁ = v ₂ = 55.9867. It can be seen that the parameters of the lens group all satisfy the foregoing first relationship and the foregoing other preset relationships. Under the above parameters, Figures 14 to 16 are the relative illuminance map, astigmatism map, TV distortion map and MFT map of the lens group in this order.

From the simulation diagrams shown in Figs. 14 to 16, it can be concluded that the FOV of the lens group is 105 degrees, the working F number is 1.41653, the TV distortion is 1.32%, and the relative illumination is 30%. Therefore, in the case where the parameters of the lens group satisfy the aforementioned first relationship, the lens group has the performance of large FOV, small working F-number, small TV distortion, and high relative illuminance.

It should be understood that the positions corresponding to the parameters in Tables 1 to 6 are blank, indicating that there is no such parameter or the value of this parameter is 0. For example, the blank space in the column of material can represent air; for another example, the blank space at the coefficient A2 of the aspheric higher order term means that the coefficient is 0.

In summary, the lens group of the embodiment of the present application provides a wide-angle short-focus lens group, which can collect fingerprint information of a larger area, and the short-focus design makes the lens group better applicable to limited vertical space On the electronic device, the applicability of the lens group is enhanced.

FIG. 17 is a schematic block diagram of a fingerprint recognition apparatus according to an embodiment of the present application. As shown in FIG. 17, the fingerprint recognition apparatus 1700 includes a lens system 1710. The lens system 1710 may include one lens group, or include two lens groups. Further expand the area of the fingerprint collection area. Each lens group may be, for example, the lens group 30 in the foregoing embodiment.

When the fingerprint identification device 1700 includes two of the lens groups, the two lens groups are arranged side by side in the radial direction, for example, as shown in FIG. 18, to further expand the field of view and reduce the lens system The total length of the fingerprint recognition device 1700 reduces the longitudinal space of the fingerprint recognition device 1700 occupied during assembly.

Since the fingerprint identification device in the embodiment of the present application uses the above lens group, and by arranging two side by side lens groups in the fingerprint identification device, it effectively solves the problem of expanding the area of the fingerprint collection area and reducing the length of the lens system Contradiction. The total length of the lens system can be less than 2.6mm, and the field of view of 4 × 7mm can be realized, that is, the fingerprint collection area of the fingerprint recognition device can reach 4 × 7mm, so that more fingerprint information of the user ’s finger can be obtained and improved Reliability of fingerprint detection, and enhance user experience when performing fingerprint detection.

Optionally, the fingerprint recognition device 1700 may include an optical fingerprint sensor 1720 such as DIE 403 shown in FIG. 4, which is disposed below the lens system 1710 and is used to receive the optical signal transmitted by the lens system 1710, and The optical signal is processed to obtain fingerprint information included in the optical signal.

Optionally, the fingerprint identification device 1700 may include an optical fingerprint sensor, and the optical fingerprint sensor 1720 may include two sensor arrays, each sensor array corresponds to a lens group, and each lens group corresponds to a sub-region in the fingerprint collection area Each lens group is used to guide the optical signal in its corresponding sub-region to the corresponding sensing array under the lens group. Alternatively, the fingerprint identification device 1700 may include two optical fingerprint sensors, the two optical fingerprint sensors respectively corresponding to the two lens groups, wherein each lens group is used for light in the sub-region corresponding to the lens group The signal is directed to its corresponding optical fingerprint sensor and collected by the sensing array on the optical fingerprint sensor.

Optionally, the fingerprint identification device 1700 may correspond to the optical fingerprint identification device 400 shown in FIG. 4, and the fingerprint identification device 1700 may further include the structure in the optical fingerprint identification device 400, such as an IR filter 301, a bracket 407, etc. , I wo n’t go into details here.

It should be understood that FIG. 18 is only a schematic illustration. In a specific implementation, the above two lens groups arranged side by side may be disposed under the same display screen. As shown in FIG. 20, the imaging area of the two lens groups on the display screen constitutes a fingerprint collection area on the display screen And the two imaging areas may have a certain overlapping area. On the other hand, the optical fingerprint sensor (or optical fingerprint sensor chip, optical imaging chip, image sensor chip, etc.) below the two lens groups can be correspondingly provided with two sensor arrays, and the two sensor arrays are covered above There are filters or IR filters. Based on the above structure, the fingerprint collection range of the two sensor arrays may respectively correspond to the two imaging areas of the above lens group, and the two sensor arrays respectively detect the fingerprint image pressed on the fingerprint collection area of the display screen. A part (called a sub-image), and the images collected in the overlapping area can be used to stitch the sub-images collected in the two imaging regions to obtain a fingerprint image of a larger area.

It should be understood that the embodiments of the present application only take the fingerprint identification device including one or two lens groups as an example for description, but may include more lens groups, which are not limited herein.

An embodiment of the present application further provides an electronic device. As shown in FIG. 19, the electronic device 1900 includes a fingerprint identification device 1910. The fingerprint identification device 1910 may be the fingerprint identification device 1700 in the foregoing embodiment, or shown in FIG. The optical fingerprint identification device 400 in the embodiment.

Optionally, the electronic device may further include a screen assembly 1920, including a display screen, foam, and copper foil, which are disposed above the lens system in the fingerprint identification device 1910; wherein, the corresponding The foam and the area of the copper foil are perforated to enable the optical signal including fingerprint information to enter the lens system.

As an example and not a limitation, the electronic device 1900 may be a terminal device, a mobile phone, a tablet computer, a notebook computer, a desktop computer, an in-vehicle electronic device, or a wearable smart device. Can not rely on smart phones to achieve complete or partial functions, such as smart watches or smart glasses, and only focus on a certain type of application functions, which need to be used in conjunction with other devices such as smart phones, such as various smart bracelets for sign monitoring , Smart jewelry and other equipment.

It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art to better understand the embodiments of the present application, rather than limit the scope of the embodiments of the present application, and those skilled in the art may base on the above embodiments Various improvements and modifications are made, and these improvements or modifications fall within the protection scope of the present application.

The above is only the specific implementation of this application, but the scope of protection of this application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in this application. It should be covered by the scope of protection of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (20)

A lens group characterized by comprising a first lens and a second lens arranged in order from the object side to the image side, wherein: The first lens includes a first lens of negative power, the first lens is an S-shaped meniscus lens with a convex surface on the object side, and at least one of the two surfaces of the first lens is aspheric; The second lens includes a positive power second lens, the second lens is a biconvex lens, and at least one of the two surfaces of the second lens is aspheric; Wherein, the parameters of the lens group satisfy the first relationship, so that the FOV of the lens group is greater than the first threshold, and the length of the lens group is less than the second threshold, The parameters of the lens group include at least two of the following: the focal length f of the lens group, the focal length f ₁ of the first lens, the focal length f _{2 of} the second lens, and the focal length of the first lens A radius of curvature R1 toward the object side, a radius of curvature R2 toward the image side of the first lens, a radius of curvature R3 toward the object side of the second lens, and a radius toward the image side of the second lens Radius of curvature R4. The lens assembly according to claim 1, wherein said first relationship _{comprises: 2.5 <f 1 / R1 <} 4 and / or 0.5 <f ₁ /R2<2.0. The lens group according to claim 1 or 2, wherein the first relationship further includes: 0.2 <f ₂ /R3<0.5 and / or -2 <f ₂ / R4 <-1. The lens group according to any one of claims 1 to 3, wherein the first relationship further includes at least one of the following: -1 <f / f ₁ <0, 0 <f / f ₂ <1, -8 <f ₁ / f ₂ <-4. The lens group according to any one of claims 1 to 4, wherein the first relationship further includes at least one of the following: 0.2 <R1 / R2 <0.5, -1 <R1 / R3 <- 0.4, 2 <R1 / R4 <4, -3 <R2 / R3 <-1, 5 <R2 / R4 <12, -8 <R3 / R4 <-3. The lens group according to any one of claims 1 to 5, wherein the first threshold is 100 degrees. The lens group according to any one of claims 1 to 6, wherein the second threshold is 2.6 mm. The lens group according to any one of claims 1 to 7, wherein the thickness CT1 of the first lens along the optical axis and the thickness CT2 of the second lens along the optical axis satisfy: 0.5 <CT1 / CT2 <1.5. The lens group according to any one of claims 1 to 8, wherein the distance TTL from the lower surface of the display screen to the imaging surface and the focal length f of the lens group satisfy: 0.1 <f / TTL <0.2 . The lens group according to any one of claims 1 to 9, wherein the maximum image height Y 'on the imaging surface of the lens group, the distance TTL from the lower surface of the display screen to the imaging surface, and the lens The focal length f of the group satisfies: 0.45 <Y '/ (f * TTL) <0.6. The lens group according to any one of claims 1 to 10, wherein the refractive index n ₁ of the material of the first lens is greater than 1.54, and the dispersion coefficient v ₁ of the material of the first lens is greater than 55.50. The lens group according to any one of claims 1 to 11, wherein the refractive index of the material of the second lens n ₂ > 1.54, and the dispersion coefficient of the material of the second lens v ₂ > 55.98. The lens group according to any one of claims 1 to 12, wherein the lens group further comprises: The diaphragm is disposed between the first lens and the second lens. The lens group according to any one of claims 1 to 13, wherein the TV distortion of the lens group is less than 5%, and / or the relative illuminance of the lens group is greater than 30%, and / or The F number of the lens group is less than 1.5. A fingerprint recognition device, characterized by comprising a lens system, the lens system comprising one lens group according to any one of claims 1 to 14, or two lens groups arranged side by side in a radial direction . The fingerprint identification device according to claim 15, wherein the fingerprint identification device further comprises: The optical fingerprint sensor is disposed under the lens system, and is used to receive the optical signal transmitted by the lens system and process the optical signal to obtain fingerprint information carried in the optical signal. The fingerprint identification device according to claim 15 or 16, wherein the area of the fingerprint collection area of the optical fingerprint sensor is greater than 4 mm × 7 mm. The fingerprint identification device according to any one of claims 15 to 17, wherein the fingerprint identification device further comprises: a bracket; Wherein, the lens system is assembled in the bracket with interference. An electronic device, characterized by comprising the fingerprint identification device according to any one of claims 15 to 18. The electronic device according to claim 19, wherein the electronic device further comprises: The screen assembly, including the display screen, foam and copper foil, is arranged above the lens system in the fingerprint identification device; Wherein, the corresponding regions of the foam and the copper foil above the lens system are perforated to allow the optical signal including fingerprint information to enter the lens system.

Images